1.3 AS 90932 Demonstrate understanding of aspects of carbon chemistry (4 credits)
INTRODUCTION TO CARBON CHEMISTRY
NCEA PAST EXAM QUESTION: Draw the chemical structure or structural formula or displayed formula for the following organic molecules
Draw the structural formula for every organic substance named in the table above, you may find it useful to print the questions on where there is space provided to draw the diagrams.
After completing the structural formulas to the best of your ability, look at the answers and correct the diagrams yourself. Print a table of questions on structural formula that have not yet appeared in the NCEA Exams, complete the table and mark it yourself using the answers provided.
PROPERTIES (solubility in water and trends in melting and boiling points) OF CARBON COMPOUNDS
NCEA PAST EXAM QUESTIONS on Properties (solubility and trends in melting and boiling points) of carbon compounds
The boiling point for methanol is 65ºC and ethanol is 78ºC. Why does ethanol have a higher boiling point than methanol?
(ii) Why are both methanol and ethanol soluble in water?
Butane and propane are both used as fuel in camping burners. Propane has a boiling point of – 42°C.
(i) What state would propane be at room temperature (18°C)?
State whether the boiling point of butane will be higher or lower than propane. Give a reason for your answer using your knowledge of the structure and properties of alkanes.
1 a) Alkanes and alkenes are organic compounds made up of carbon and hydrogen atoms. Name the type of bonding that occurs between the atoms in these organic compounds. Explain your answer.
b) Explain how the chemical bonding in alkanes and alkenes affects the way they are used In your answer:
• give the general formulae of alkanes and alkenes
• describe the similarities and differences in chemical bonding
• identify ONE common use for each of alkanes and alkenes
• link the chemical bonding to the property or properties of each type of compound that makes them suitable for the identified use.
2)The boiling points of some alkanes are shown in the graph below
Analyse the trend in boiling points of the first eight alkanes, as shown in the graph above. In your answer:
• describe the trend
• explain why this trend occurs.
Identify the type of bonding within a molecule of methanol. Give a reason for your choice.
Analyse the differences between ethane and ethanol by considering the similarities and differences of their chemical structures and their physical properties. In your answer include, for both ethane and ethanol:
• their state at room temperature
• their relative melting and boiling points
• their solubility in water.
Identify and explain the trend of boiling points for the alkanes shown in the graph above.
In October 2011 a ship, the Rena, grounded on a reef near Tauranga Harbour, causing oil to be spilled into the ocean. It was observed that the oil formed a layer on top of the water, and that it lasted for a long time. Give an explanation for both observations by referring to the properties of oil.
Hexane and ethanol are organic compounds, which are liquid at room temperature.
Using only water and a Bunsen burner, explain one chemical AND one physical test that could be used to identify hexane and ethanol.
Your answer must include:
• a description of each test
• the observations that would be made for each test for BOTH compounds
• an explanation of the chemical and physical properties of BOTH compounds that allow identification with your tests.
Melting and boiling points of alkanes
Discuss the trend in the melting and boiling points for the first eight alkanes. In your answer, you should
- define the terms melting point and boiling point
- identify the state of the alkanes with three AND with six carbon atoms at room temperature
- explain what happens to the particles in a substance when melting and boiling occur
- fully explain why both the boiling points and melting points of the first eight alkanes tend to rise as the number of carbon atoms increases.
The graph below shows the trend of boiling points for the first six alkanes.
Describe the trend shown in the graph of the boiling points for the first six alkanes and explain why this trend occurs.
Identify the compound(s) in the table below that would be soluble in water
Two of the compounds in the table above are gases and two are liquids at room temperature. State which compounds are liquid at room temperature.
Hexane and ethanol are two colourless liquids.
Compare the chemical and physical properties of these two compounds, and use this comparison to describe how to safely distinguish between these two liquids.
Name TWO organic compounds in the table below that are insoluble in water.
PROPERTIES: COMPLETE AND INCOMPLETE COMBUSTION REACTIONS
and
USES AND IMPORTANCE OF FUELS
and
EFFECTS OF COMBUSTION PRODUCTS ON HUMAN HEALTH AND THE ENVIRONMENT
NCEA PAST EXAM QUESTION: Write balanced equations for the complete and incomplete complete combustion of the following molecules
ADDITIONAL NCEA QUESTIONS ON COMBUSTION
Alkanes can be used as fuels. Compare and contrast: the complete combustion of alkanes, which produces carbon dioxide; and the incomplete combustion,
which produces carbon monoxide and carbon in addition to carbon dioxide. In your answer, you should:
• use butane as an example to illustrate your answer
• give an explanation of an effect on the environment for TWO combustion products
• include balanced symbol equations for the reactions occurring, in the labelled boxes below.
Camping burners usually have a warning notice instructing people to always use them in a well-ventilated place (plenty of oxygen) otherwise serious injury
or death may occur. Elaborate on why this warning is given on camping burners. Use a burner that contains propane as an example. In your answer, you should:
• state the type of combustion reaction that occurs when there is a shortage of oxygen
• describe the observations that may be seen if there was a shortage of oxygen, and link these to the reaction occurring
• explain two effects that the combustion products can have on human health when there is a shortage of oxygen
• write a word equation and a balanced symbol equation for the reaction occurring.
Methanol and methane are commonly used in fuels. Methanol burns with an almost colourless flame. Methane, if there is a limited supply of oxygen, burns with
an orange flame. Explain the process and effects of complete and incomplete combustion reactions, using methanol and methane as examples.
In your answer:
• describe both types of combustion reactions
• elaborate on ONE effect each of complete AND incomplete combustion can have on EITHER human health OR the environment
• relate your explanation to the combustion of methanol and methane
• write ONE appropriate balanced symbol equation.
Compare and contrast the complete combustion of methanol to the incomplete combustion of octane. In your answer:
• compare and contrast the combustion reactions of both fuels
• compare and contrast the impacts of the combustion products of both fuels on human health or the environment
• write a balanced symbol equation for the complete combustion of methanol.
1) Ethanol burns in air with an almost invisible flame. State the type of combustion reaction ethanol undergoes and name the products formed.
Identify and evaluate ONE effect that a product of the complete combustion reaction for ethanol would have on the environment.
2)Ethene burns with a smoky flame in a limited oxygen supply. Identify and explain TWO negative effects on human health of the products of this combustion reaction.
1) Both butane and methanol can be used as fuels. A sample of butane burns in air with a yellow flame, while a sample of methanol burns in air with an almost invisible flame. Compare and contrast the combustion of these two fuels.
2) Combustion of fuels can have negative effects on both human health and the environment. Identify and explain TWO negative effects of the combustion of fuels on both human health and the environment. Your answer should include:
ONE negative effect on human health, and
ONE negative effect on the environment.
Propane and methanol are carbon compounds that are used as fuels. When propane is burning with an orange flame it produces soot. When methanol is burning with an almost invisible flame it produces no soot.
Discuss the effect on the environment of burning propane and methanol as described above. In your answer, you should:
explain how the combustion of propane and the combustion of methanol differ
identify which combustion reaction has the greater negative effect on the environment and justify your answer
Discuss TWO impacts (positive or negative) that the products of the complete combustion of methanol would have on the environment.
Pentane and ethanol are two colourless organic liquids that can be used as fuels. Discuss the similarities and differences for the combustion of both fuels. Include in your answer:
the observations made when each fuel is burned
the impact of combustion on the environment for each fuel.
Propane and ethanol are organic compounds used as fuel. Propane burns with an orange flame and some soot forms. Ethanol burns with an almost invisible flame with no soot forming. By considering the products of these reactions, predict and justify which fuel will have the larger impact on people.
Include examples of how people would be affected.
State TWO reasons why organic compounds such as butane are used as fuels. Explain the difference between complete and incomplete combustion of fuels.
If insufficient oxygen is available in a car engine, incomplete combustion can occur. Describe incomplete combustion and discuss its impact on human health.
Compare ethanol and propane in terms of:
• the impact of the combustion of each fuel on people and the global environment
• the energy produced by the burning of each fuel
• safety considerations in handling and storing the fuels.
PROPERTIES: POLYMERISATION REACTIONS OF ETHENE AND PROPENE
and
USES AND IMPORTANCE OF POLYMERS FROM ETHENE AND PROPENE
NCEA PAST EXAM QUESTION: Outline fully the chemical reaction for form the following polymers
Octane can be used to produce the polymer, polyethene. Octane undergoes Reaction 1 to form hexane and Product 2. Product 2 can be used to produce
polyethene.
(i) Complete the reaction scheme by filling in the boxes to show all structural formulae, as well as the name for Product 2.
(ii) Elaborate on Reaction 1 and Reaction 2. In your answer, you should:
• name the types of reactions occurring
• give the conditions required for each reaction
• explain how polyethene can be made from Product 2.
Explain how the structure of ethene allows it to form polyethene
1) Polymers are very large molecules made up of many small repeating units. Explain why an alkene such as ethene can be used to make polymers, while an alkane such as ethane cannot. You may draw diagrams as part of your explanation.
2) Polymers are used in the production of plastics. Plastic pollution is becoming a planet-wide problem, with much of the waste plastic ending up in our oceans. Polyethene (polythene) and polypropene (polypropylene) both float on the ocean’s surface, forming part of the large floating islands of plastic waste that form where ocean currents meet.
Explain why the polymers polyethene and polypropene form part of these floating islands of plastic. In your answer:
• describe the chemical structure and bonding of these polymers
• explain the chemical reactivity of these polymers.
Explain why alkenes can be used to make polymers, but alkanes cannot.
Polypropene (polypropylene) has many uses that are linked to its chemical and physical properties. Name TWO uses of polypropene.
Link each use to TWO physical and / or chemical properties of polypropene.
Polyethene is available in both a low density (LDPE) and high density (HDPE) form. Some properties of LDPE and HDPE are given in the table below.
Explain why LDPE is used to make plastic food wrap and HDPE is used to make plastic drink bottles, by analysing the properties provided in the table above. Explain why polyethene is a non-biodegradable substance.
Outline in full the chemical reaction that occurs between propene molecules to form the polymer polypropene.
Polypropene has many uses that are related to its properties. Describe TWO uses of polypropene and link these uses to named physical and chemical properties of polypropene.
Ethene is used to make the polymer polyethene. Polyethene has many different uses, for example plastic bags. Some uses of polyethene rely on its toughness.
Discuss the process of the polymerisation of ethene into polyethene. In you answer, you should:
Explain why polyethene is tough by referring to its chemical structure
Ethene is a useful chemical. It is used to make many useful products such as polymers. What is a polymer?
Explain how ethene molecules join together to form polyethene. Include in your answer the conditions required for this reaction to occur.
NCEA PAST EXAM QUESTIONS on Fractional Distillation
Crude oil undergoes fractional distillation in tall towers. The different fractions produced have many uses.
(a) Name TWO of the fractions obtained from a fractional distillation tower, and describe ONE use for each.
(b) (i) Why does crude oil need to undergo fractional distillation before it can be used?
(ii) Explain why fractional distillation is carried out in tall towers.
In your answer you should link the process of fractional distillation to the physical properties and chemical structure of the hydrocarbons in crude oil.
Give a detailed account of the process by which crude oil is seperated into useful products In your answer, you should:
• explain why this process is necessary
• elaborate on what occurs during this process, and link this to the structure and properties of the hydrocarbons in crude oil.
• name two products, other than dodecane, C12H26 that are formed.
Crude oil is fractionally distilled in tall towers to obtain useful products.
(a) Explain why crude oil must be fractionally distilled before it can be used.
(b) Name TWO of the fractions obtained from the fractional distillation tower, and describe ONE use for each.
(c)Explain why fractional distillation is carried out in towers.
You will need to refer to the chemical structure and physical properties of the hydrocarbons that make up crude oil, and the way the fractional distillation tower operates.
Give a detailed account of the fractional distillation of crude oil.In your answer you should:
• describe the composition of crude oil
• explain how the process of fractional distillation is carried out
• link the process of fractional distillation to the physical properties and chemical structure of hydrocarbons.
Discuss the fractional distillation of crude oil. In your answer, you should describe the composition of crude oil
• explain how the physical properties of hydrocarbons allow them to be separated by fractional distillation
• Fully explain how these physical properties are related to the chemical structure of hydrocarbons.
Discuss how crude oil can be separated into its components using fractional distillation. In your answer, outline what crude oil is and refer to the physical properties of hydrocarbons.
Use the physical properties of hydrocarbons to explain how crude oil can be separated into its components using the process of fractional distillation. You may label the diagram below and refer to it in your explanation.
Dodecane, C12H26, can be reacted in to form ethene and octane.
(i) State one condition that is needed.
(ii) Complete the following balanced symbol equation for the reaction of dodecane.
C12H26 →
Cracking is a process used to break down the long-chain alkanes found in crude oil, into smaller molecules.
(a) Complete a balanced symbol equation to show how the long-chain alkane decane, C10H22, breaks down to form pentane, ethene, and propene.
(b) Explain why some long-chain alkanes need to undergo cracking.
Crude oil is made up of different fractions. Some of these fractions contain large chain hydrocarbons that may not be useful as fuels.
Cracking is the process used to produce smaller, more useful hydrocarbons. Give a detailed account of the process of cracking. In your answer you should:
• describe the process of cracking, stating the conditions required
• explain why the large chain fractions may not be useful as fuels
• by using hexane as an example, identify the products that would form in cracking, and explain why they form by referring to their chemical structures
• give ONE use for each of the products that form.
How does the industrial preparation of methanol from natural gas differ from the process of fermentation to form ethanol?
In your answer, you should include:
• a description of the two processes
• explanations of any conditions required
• balanced symbol equations for any reactions occurring
One method of producing ethanol is by fermentation.Explain how ethanol is produced by fermentation.
In your answer, you should:
• complete the following word equation and balanced symbol equations
• identify and elaborate on any conditions required for fermentation to occur.
glucose →
C6H12O6→
Fermentation is one method that can be used to produce ethanol. Elaborate on how fermentation is used to produce ethanol. In your answer include:
• an explanation of the materials used and the products obtained
• the conditions required for fermentation to occur
• a balanced symbol equation.
Outline the fermentation process that produces ethanol from glucose (C6H12O6). Include the conditions required for this process to occur, and a balanced symbol equation.
Ethanol is a fuel obtained by fermenting glucose(C6H12O6). Discuss the process of fermenting glucose into ethanol. In your answer, you should:
fully explain how the fermentation process works
write a balanced symbol equation for the process.
Two uses of alcohols are in beverages (such as beer and wine), and as fuels.
Alcoholic beverages are made with ethanol. One way of making ethanol is by the process of fermentation.
Give an account of the process of fermentation. Your answer should include:
• the starting materials used and the products which are formed
• the conditions required for fermentation to occur
• a word equation for the fermentation reaction, showing all the reactants and products.
INTRODUCTION TO CARBON CHEMISTRY
NCEA PAST EXAM QUESTION: Draw the chemical structure or structural formula or displayed formula for the following organic molecules
After completing the structural formulas to the best of your ability, look at the answers and correct the diagrams yourself. Print a table of questions on structural formula that have not yet appeared in the NCEA Exams, complete the table and mark it yourself using the answers provided.
NCEA PAST EXAM QUESTION: Name the following organic molecules
PROPERTIES (solubility in water and trends in melting and boiling points) OF CARBON COMPOUNDS
NCEA PAST EXAM QUESTIONS on Properties (solubility and trends in melting and boiling points) of carbon compounds
The boiling point for methanol is 65ºC and ethanol is 78ºC. Why does ethanol have a higher boiling point than methanol?
(ii) Why are both methanol and ethanol soluble in water?
Butane and propane are both used as fuel in camping burners. Propane has a boiling point of – 42°C.
(i) What state would propane be at room temperature (18°C)?
State whether the boiling point of butane will be higher or lower than propane. Give a reason for your answer using your knowledge of the structure and properties of alkanes.
1 a) Alkanes and alkenes are organic compounds made up of carbon and hydrogen atoms. Name the type of bonding that occurs between the atoms in these organic compounds. Explain your answer.
b) Explain how the chemical bonding in alkanes and alkenes affects the way they are used In your answer:
• give the general formulae of alkanes and alkenes
• describe the similarities and differences in chemical bonding
• identify ONE common use for each of alkanes and alkenes
• link the chemical bonding to the property or properties of each type of compound that makes them suitable for the identified use.
2)The boiling points of some alkanes are shown in the graph below
Analyse the trend in boiling points of the first eight alkanes, as shown in the graph above. In your answer:
• describe the trend
• explain why this trend occurs.
Identify the type of bonding within a molecule of methanol. Give a reason for your choice.
Analyse the differences between ethane and ethanol by considering the similarities and differences of their chemical structures and their physical properties. In your answer include, for both ethane and ethanol:
• their state at room temperature
• their relative melting and boiling points
• their solubility in water.
Identify and explain the trend of boiling points for the alkanes shown in the graph above.
In October 2011 a ship, the Rena, grounded on a reef near Tauranga Harbour, causing oil to be spilled into the ocean. It was observed that the oil formed a layer on top of the water, and that it lasted for a long time. Give an explanation for both observations by referring to the properties of oil.
Hexane and ethanol are organic compounds, which are liquid at room temperature.
Using only water and a Bunsen burner, explain one chemical AND one physical test that could be used to identify hexane and ethanol.
Your answer must include:
• a description of each test
• the observations that would be made for each test for BOTH compounds
• an explanation of the chemical and physical properties of BOTH compounds that allow identification with your tests.
Melting and boiling points of alkanes
Discuss the trend in the melting and boiling points for the first eight alkanes. In your answer, you should
- define the terms melting point and boiling point
- identify the state of the alkanes with three AND with six carbon atoms at room temperature
- explain what happens to the particles in a substance when melting and boiling occur
- fully explain why both the boiling points and melting points of the first eight alkanes tend to rise as the number of carbon atoms increases.
The graph below shows the trend of boiling points for the first six alkanes.
Describe the trend shown in the graph of the boiling points for the first six alkanes and explain why this trend occurs.
Identify the compound(s) in the table below that would be soluble in water
Two of the compounds in the table above are gases and two are liquids at room temperature. State which compounds are liquid at room temperature.
Hexane and ethanol are two colourless liquids.
Compare the chemical and physical properties of these two compounds, and use this comparison to describe how to safely distinguish between these two liquids.
Name TWO organic compounds in the table below that are insoluble in water.
PROPERTIES: COMPLETE AND INCOMPLETE COMBUSTION REACTIONS
and
USES AND IMPORTANCE OF FUELS
and
EFFECTS OF COMBUSTION PRODUCTS ON HUMAN HEALTH AND THE ENVIRONMENT
NCEA PAST EXAM QUESTION: Write balanced equations for the complete and incomplete complete combustion of the following molecules
ADDITIONAL NCEA QUESTIONS ON COMBUSTION
Alkanes can be used as fuels. Compare and contrast: the complete combustion of alkanes, which produces carbon dioxide; and the incomplete combustion,
which produces carbon monoxide and carbon in addition to carbon dioxide. In your answer, you should:
• use butane as an example to illustrate your answer
• give an explanation of an effect on the environment for TWO combustion products
• include balanced symbol equations for the reactions occurring, in the labelled boxes below.
Camping burners usually have a warning notice instructing people to always use them in a well-ventilated place (plenty of oxygen) otherwise serious injury
or death may occur. Elaborate on why this warning is given on camping burners. Use a burner that contains propane as an example. In your answer, you should:
• state the type of combustion reaction that occurs when there is a shortage of oxygen
• describe the observations that may be seen if there was a shortage of oxygen, and link these to the reaction occurring
• explain two effects that the combustion products can have on human health when there is a shortage of oxygen
• write a word equation and a balanced symbol equation for the reaction occurring.
Methanol and methane are commonly used in fuels. Methanol burns with an almost colourless flame. Methane, if there is a limited supply of oxygen, burns with
an orange flame. Explain the process and effects of complete and incomplete combustion reactions, using methanol and methane as examples.
In your answer:
• describe both types of combustion reactions
• elaborate on ONE effect each of complete AND incomplete combustion can have on EITHER human health OR the environment
• relate your explanation to the combustion of methanol and methane
• write ONE appropriate balanced symbol equation.
Compare and contrast the complete combustion of methanol to the incomplete combustion of octane. In your answer:
• compare and contrast the combustion reactions of both fuels
• compare and contrast the impacts of the combustion products of both fuels on human health or the environment
• write a balanced symbol equation for the complete combustion of methanol.
1) Ethanol burns in air with an almost invisible flame. State the type of combustion reaction ethanol undergoes and name the products formed.
Identify and evaluate ONE effect that a product of the complete combustion reaction for ethanol would have on the environment.
2) Ethene burns with a smoky flame in a limited oxygen supply.Identify and explain TWO negative effects on human health of the products of this combustion reaction.
1) Both butane and methanol can be used as fuels. A sample of butane burns in air with a yellow flame, while a sample of methanol burns in air with an almost invisible flame. Compare and contrast the combustion of these two fuels.
2) Combustion of fuels can have negative effects on both human health and the environment. Identify and explain TWO negative effects of the combustion of fuels on both human health and the environment. Your answer should include:
ONE negative effect on human health, and
ONE negative effect on the environment.
Propane and methanol are carbon compounds that are used as fuels. When propane is burning with an orange flame it produces soot. When methanol is burning with an almost invisible flame it produces no soot.
Discuss the effect on the environment of burning propane and methanol as described above. In your answer, you should:
explain how the combustion of propane and the combustion of methanol differ
identify which combustion reaction has the greater negative effect on the environment and justify your answer
Discuss TWO impacts (positive or negative) that the products of the complete combustion of methanol would have on the environment.
Pentane and ethanol are two colourless organic liquids that can be used as fuels. Discuss the similarities and differences for the combustion of both fuels. Include in your answer:
the observations made when each fuel is burned
the impact of combustion on the environment for each fuel.
Propane and ethanol are organic compounds used as fuel. Propane burns with an orange flame and some soot forms. Ethanol burns with an almost invisible flame with no soot forming. By considering the products of these reactions, predict and justify which fuel will have the larger impact on people.
Include examples of how people would be affected.
State TWO reasons why organic compounds such as butane are used as fuels. Explain the difference between complete and incomplete combustion of fuels.
If insufficient oxygen is available in a car engine, incomplete combustion can occur. Describe incomplete combustion and discuss its impact on human health.
Compare ethanol and propane in terms of:
• the impact of the combustion of each fuel on people and the global environment
• the energy produced by the burning of each fuel
• safety considerations in handling and storing the fuels.
PROPERTIES: POLYMERISATION REACTIONS OF ETHENE AND PROPENE
and
USES AND IMPORTANCE OF POLYMERS FROM ETHENE AND PROPENE
NCEA PAST EXAM QUESTION: Outline fully the chemical reaction for form the following polymers
Octane can be used to produce the polymer, polyethene. Octane undergoes Reaction 1 to form hexane and Product 2. Product 2 can be used to produce
polyethene.
(i) Complete the reaction scheme by filling in the boxes to show all structural formulae, as well as the name for Product 2.
(ii) Elaborate on Reaction 1 and Reaction 2. In your answer, you should:
• name the types of reactions occurring
• give the conditions required for each reaction
• explain how polyethene can be made from Product 2.
Explain how the structure of ethene allows it to form polyethene
1) Polymers are very large molecules made up of many small repeating units. Explain why an alkene such as ethene can be used to make polymers, while an alkane such as ethane cannot. You may draw diagrams as part of your explanation.
2) Polymers are used in the production of plastics. Plastic pollution is becoming a planet-wide problem, with much of the waste plastic ending up in our oceans. Polyethene (polythene) and polypropene (polypropylene) both float on the ocean’s surface, forming part of the large floating islands of plastic waste that form where ocean currents meet.
Explain why the polymers polyethene and polypropene form part of these floating islands of plastic. In your answer:
• describe the chemical structure and bonding of these polymers
• explain the chemical reactivity of these polymers.
Explain why alkenes can be used to make polymers, but alkanes cannot.
Polypropene (polypropylene) has many uses that are linked to its chemical and physical properties. Name TWO uses of polypropene.
Link each use to TWO physical and / or chemical properties of polypropene.
Polyethene is available in both a low density (LDPE) and high density (HDPE) form. Some properties of LDPE and HDPE are given in the table below.
Explain why LDPE is used to make plastic food wrap and HDPE is used to make plastic drink bottles, by analysing the properties provided in the table above. Explain why polyethene is a non-biodegradable substance.
Outline in full the chemical reaction that occurs between propene molecules to form the polymer polypropene.
Polypropene has many uses that are related to its properties. Describe TWO uses of polypropene and link these uses to named physical and chemical properties of polypropene.
Ethene is used to make the polymer polyethene. Polyethene has many different uses, for example plastic bags. Some uses of polyethene rely on its toughness.
Discuss the process of the polymerisation of ethene into polyethene. In you answer, you should:
Explain why polyethene is tough by referring to its chemical structure
Ethene is a useful chemical. It is used to make many useful products such as polymers. What is a polymer?
Explain how ethene molecules join together to form polyethene. Include in your answer the conditions required for this reaction to occur.
PRODUCTION: FRACTIONAL DISTILLATION OF CRUDE OIL
NCEA PAST EXAM QUESTIONS on Fractional Distillation
Crude oil undergoes fractional distillation in tall towers. The different fractions produced have many uses.
(a) Name TWO of the fractions obtained from a fractional distillation tower, and describe ONE use for each.
(b) (i) Why does crude oil need to undergo fractional distillation before it can be used?
(ii) Explain why fractional distillation is carried out in tall towers.
In your answer you should link the process of fractional distillation to the physical properties and chemical structure of the hydrocarbons in crude oil.
Give a detailed account of the process by which crude oil is seperated into useful products In your answer, you should:
• explain why this process is necessary
• elaborate on what occurs during this process, and link this to the structure and properties of the hydrocarbons in crude oil.
• name two products, other than dodecane, C12H26 that are formed.
Crude oil is fractionally distilled in tall towers to obtain useful products.
(a) Explain why crude oil must be fractionally distilled before it can be used.
(b) Name TWO of the fractions obtained from the fractional distillation tower, and describe ONE use for each.
(c)Explain why fractional distillation is carried out in towers.
You will need to refer to the chemical structure and physical properties of the hydrocarbons that make up crude oil, and the way the fractional distillation tower operates.
Give a detailed account of the fractional distillation of crude oil.In your answer you should:
• describe the composition of crude oil
• explain how the process of fractional distillation is carried out
• link the process of fractional distillation to the physical properties and chemical structure of hydrocarbons.
Discuss the fractional distillation of crude oil. In your answer, you should describe the composition of crude oil
• explain how the physical properties of hydrocarbons allow them to be separated by fractional distillation
• Fully explain how these physical properties are related to the chemical structure of hydrocarbons.
Discuss how crude oil can be separated into its components using fractional distillation. In your answer, outline what crude oil is and refer to the physical properties of hydrocarbons.
Use the physical properties of hydrocarbons to explain how crude oil can be separated into its components using the process of fractional distillation. You may label the diagram below and refer to it in your explanation.
PRODUCTION: CRACKING OF FRACTIONS
NCEA PAST EXAM QUESTIONS on Cracking of fractions
Dodecane, C12H26, can be reacted in to form ethene and octane.
(i) State one condition that is needed.
(ii) Complete the following balanced symbol equation for the reaction of dodecane.
C12H26 →
Cracking is a process used to break down the long-chain alkanes found in crude oil, into smaller molecules.
(a) Complete a balanced symbol equation to show how the long-chain alkane decane, C10H22, breaks down to form pentane, ethene, and propene.
(b) Explain why some long-chain alkanes need to undergo cracking.
Crude oil is made up of different fractions. Some of these fractions contain large chain hydrocarbons that may not be useful as fuels.
Cracking is the process used to produce smaller, more useful hydrocarbons. Give a detailed account of the process of cracking. In your answer you should:
• describe the process of cracking, stating the conditions required
• explain why the large chain fractions may not be useful as fuels
• by using hexane as an example, identify the products that would form in cracking, and explain why they form by referring to their chemical structures
• give ONE use for each of the products that form.
PRODUCTION: FERMENTATION
NCEA PAST EXAM QUESTIONS on Fermentation
How does the industrial preparation of methanol from natural gas differ from the process of fermentation to form ethanol?
In your answer, you should include:
• a description of the two processes
• explanations of any conditions required
• balanced symbol equations for any reactions occurring
One method of producing ethanol is by fermentation.Explain how ethanol is produced by fermentation.
In your answer, you should:
• complete the following word equation and balanced symbol equations
• identify and elaborate on any conditions required for fermentation to occur.
glucose →
C6H12O6→
Fermentation is one method that can be used to produce ethanol. Elaborate on how fermentation is used to produce ethanol. In your answer include:
• an explanation of the materials used and the products obtained
• the conditions required for fermentation to occur
• a balanced symbol equation.
Outline the fermentation process that produces ethanol from glucose (C6H12O6). Include the conditions required for this process to occur, and a balanced symbol equation.
Ethanol is a fuel obtained by fermenting glucose(C6H12O6). Discuss the process of fermenting glucose into ethanol. In your answer, you should:
fully explain how the fermentation process works
write a balanced symbol equation for the process.
Two uses of alcohols are in beverages (such as beer and wine), and as fuels.
Alcoholic beverages are made with ethanol. One way of making ethanol is by the process of fermentation.
Give an account of the process of fermentation. Your answer should include:
• the starting materials used and the products which are formed
• the conditions required for fermentation to occur
• a word equation for the fermentation reaction, showing all the reactants and products.
PRODUCTION: METHANOL FROM NATURAL GAS
NCEA PAST EXAM QUESTIONS on METHANOL from natural gas
How does the industrial preparation of methanol from natural gas differ from the process of fermentation to form ethanol?
In your answer, you should include:
• a description of the two processes
• explanations of any conditions required
• balanced symbol equations for any reactions occurring
In New Zealand methanol is produced from natural gas, methane, extracted from the Taranaki gas fields.
(a) Draw the chemical structures for methane and for methanol.
Write balanced symbol equations for both of the reactions involved in the production of methanol from methane.
(i) Reaction 1: Methane and steam are reacted using a nickel catalyst, Ni, and a strong heat source, to form carbon monoxide gas and hydrogen gas.
(ii) Reaction 2: Carbon monoxide gas and hydrogen gas are reacted at 250oC using a copper-zinc catalyst, Cu-Zn, to form methanol.
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SciPAD (2015) Jason Rendle, Silverback Academic Media